Not applicable.
The present invention relations to holiday decorations, such as, for example, Christmas ornaments and lights, and more particularly to such decorations based on holograms.
Conventional Christmas lights typically rely on colored lights or white lights shining through a colored layer in order to generate colors. A Christmas light which could generate a myriad of colors would have an appeal to the market. The same statement can be made of Christmas ornaments. While some ornaments are motorized, color typically is generated by paint or plastic laminates or by illumination with colored lights or white lights shining through a colored layer. Again, Christmas ornaments which are truly multi-colored again would have an appeal to the market.
Holograms offer a technique by which a wealth of information can be displayed optically to an observer. If the hologram is of a diffractive layer and the diffractive layer has its effective spacing changed, then the holographic diffractive layer will generate a multitude of colors to the observer by dint of such grating spacing variation. This color generation is disclosed in U.S. Pat. No. 5,613,022, the disclosure of which is expressly incorporated herein by reference. Other proposals aimed at employing holograms in the decorative fields are summarized below.
U.S. Pat. No. 5,651,741 proposes a golf ball carrying an interference pattern on its outer surface which pattern is formed by holographic recording. Holograms are stated to include Fresnel holograms, Fourier-transform holograms, plane holograms, volume holograms, or the like.
U.S. Pat. No. 5,609,928 proposes a decorative ornament formed from material, which may be holographic, and which is wound around a trapezoidal core and then cut to form thin strips of material in a decorative arrangement. No details on the holographic material are provided.
U.S. Pat. No. 5,294,494 proposes a holographic display formed from two spaced-apart transparent sheets wherein two mirrors overlay portions of the sheets such that reflective surfaces of the mirrors face each other and the first mirror is disposed on the same sheet upon which the holographic plate is mounted and is larger than the second mirror. A light source is disposed between the two sheets.
U.S. Pat. No. 5,293,259 proposes a rainbow hologram formed from a pair of spaced-apart transparent sheets with a light source disposed therebetween with the holographic plate mounted to one of the transparent sheets and a pair of mirrors of different size mounted to reflect the light source.
U.S. Pat. No. 5,155,604 proposes a decorative embossed sheet of a paper which carriers a metal coating which itself carriers a thermoplastic layer which has been embossed with a diffraction or holographic pattern while the thermoplastic layer was heated to soften it.
U.S. Pat. No. 5,121,229 proposes a compact holographic display formed from a light-transmissive plate, a hologram mounted to said plate, and means for illuminating an edge of the plate with a diverging beam of white light where such means are configured such that all reconstructive illumination enters the edge of the plate. The hologram is produced by a 3-step process including recording a first master hologram, recording a second master hologram through reconstruction of an image from a slit-like illumination of the first master hologram and recording the first mentioned hologram through reconstruction of an image from the second master hologram.
U.S. Pat. No. 4,947,299 proposes a decorative lamp having a holographic film pre-recorded with a plurality of holograms of a torch of an illuminator which film is borne by an opening in the shade wherein the torch (e.g., light bulb) illuminates the film to display a plurality of torch images.
U.S. Pat. No. 4,807,971 proposes an optical decorative apparatus which uses a drum-shaped hologram film, light equipment, and a stand having a transparent upper section to display the holographic image.
U.S. Pat. No. 4,725,511 proposes a decorative article formed from a semiconductor layer which has a patterned coating bearing a diffraction grating thereover with a transparent layer over the patterned coating. Watch faces are shown with the decorative article which emits colored light to the observed by dint of the diffraction grating.
U.S. Pat. No. 4,094,575 proposes a hologram composed of a sheet material having a permanent, optically detectable pattern which includes at least one linear grating having a pre-selected spatial frequency formed by the impingement of two mutually coherent beams of radiation along separate paths forming equal angles of incidence with a transparency in substantial contact with a photosensitive medium.
U.S. Pat. No. 2,313,489 proposes to form diffraction gratings into a carrier and then transfer them to a polymeric film in various orientations. A molding material then is placed into contact with the polymeric film to transfer the diffraction gratings to the molding material, for example, glass.
U.S. Pat. No. 4,358,487 proposes an inflatable Christmas ornament that has the appearance of a glass ornament.
U.S. Pat. No. 5,500,311 proposes holographic flake pigments made from an organic polymer and a volume hologram.
U.S. Pat. No. 734,134 proposes to make a flat planar diffractive grating by a ruling engine and transfers this grating onto a film which he then can wrap around a cylindrical glass (see FIG. 5). Such proposal requires multiple steps to get crossed gratings on an object and such gratings are constructed mechanically. This proposal also is limited to parallel lines due to limitations of a ruling engine for any set of gratings. This proposal further is limited to xe2x80x9cplanexe2x80x9d gratings or overlapping xe2x80x9cplanexe2x80x9d gratings. In order too transfer the planar gratings to the cylindrical glass, the glass surface must be photosensitive. This proposal requires chemical etching of the glass surface. Chemical etchants for glass, such as hydrofluoric acid, are known to be toxic.
Again, while a variety of decorative holograms have been proposed in the art these holograms have not been specifically applied to lights (e.g., Christmas lights) and Christmas ornaments. Such is an object of the present invention.
The present invention in its broadest aspects relates to the employment of holographic optical elements (HOE), both passively and actively, on curved surfaces which makes the invention especially useful, for example, in the construction of light bulbs (e.g., Christmas lights) and ornaments (e.g., Christmas ornaments). Broadly, then, the present invention can have one or a myriad of small holographic optical elements, which were constructed to be essentially xe2x80x9cdistortionxe2x80x9d free on said curved surface, adhered to an inside or outside curved surface of a light or an ornament. For present purposes, xe2x80x9cdistortionxe2x80x9d is an undesirable wavefront caused by light reflecting off of or transmitting through a curved surface. xe2x80x9cDistortion freexe2x80x9d, then, is the creation of the desired reconstructed wavefront, which may be spherical, cylindrical, etc. When the holographic image viewed is xe2x80x9cessentially distortion freexe2x80x9d, any distortions in the image (colors, alphanumeric characters, graphics) are not readily noticeable by the observer and, if present, are not objectionable to the observer or otherwise adversely affect the viewing of the image.
The distortion free aspect is achieved by the ability of a holographic diffraction grating to have optical xe2x80x9cpowerxe2x80x9d associated with it. When the hologram is put on a curved surface, the distortion caused by the curved surface in the diffracted wavefront can be corrected by making the hologram with a wavefront that is the conjugate of the distorted wavefront. The reconstruction of the subsequent hologram will be a plane wave and free of the distortion caused by the curved surface. Alternatively, the distortion can be controlled by how the original hologram is constructed so that the reconstructed wave can be partially spherical or cylindrical in nature. At different viewpoints of the observer, the light or ornament would (reflectively and/or transmissively) emit a rainbow of colors. This sparkling effect could be achieved simply and effectively.
Alternatively, the HOE could be active, such as is achieved in the ""022 patent so that movement of the HOE (change in the effective grating spacing of the HOE diffraction grating), such as by piezoelectric elements, magnostrictive elements, magnetic coils, and the like, generates different colors would be emitted to a stationary observer at any location of viewing.
Still further, the HOE could be molded into the Christmas light or ornament, rather than adhesively or otherwise bound thereto. Non-movement of the HOE would still cause the generation of colors passively. Movement of the HOE in the ""022 patent manner would cause a color generation by the light or ornament from a white light source (reflective and/or transmissive) in a way not heretofore recognized by the art.
In all aspects of the present invention, however, the HOE or HOP (holographic optical pattern) could be constructed to be distortion free on the curved surface. Thus, it will be seen that the present invention has the ability to provide an entirely new generation of Christmas lights and ornaments. Of course, those skilled in the art will appreciate that the use of the term xe2x80x9cChristmasxe2x80x9d is for illustration purposes only as a variety of holiday or special occasion or decorative lights and ornaments could be made in accordance with the precepts of the present invention.
Advantages of the present invention include that crossed gratings can be achieved with a single step by exposure of beams at multiple angles which saves manufacturing time. Another advantage is that the gratings are constructed non-mechanically with laser interference (no mechanical wear and tear, faster, lower cost per unit). A further advantage is that the final surface need not be photosensitive as the grating is transferred onto the surface by gluing embossed, for example, Mylar(copyright) film (E. I. du Pont de Nemours and Co.) on it or embossing directly into the final surface. A yet further advantage is that conventional etching also can be practiced. A still further advantage is that the grating lines can be any shape and this can provide enhanced color, more spectral variations in color and diffraction angle, and minimized distortion on curved surfaces. Another advantage is that the invention provides unlimited grating types. A still further advantage is that the holographic gratings can be used to compensate for distortions caused by curved surfaces. A still further advantage is that the gratings can have xe2x80x9cchirpedxe2x80x9d spatial frequencies for varying dispersions which makes spherical gratings possible that diffract over 360 degrees. These and other advantages will be readily apparent to those skilled in the art based on the disclosure set forth herein.